Decrease In Titer Research Articles

Exploring potential of graphene oxide as an alternative antiviral approach for influenza A H1N1.

Aim: Graphene oxide (GO), known for its distinctive physicochemical properties, shows promise as a nanomaterial capable of combating infectious agents. This study investigates the efficacy of GO nanoparticles in restricting influenza A H1N1 replication in MDCK cells.Methods: GO nanoparticles were synthesized. After evaluating the toxicity of GO nanoparticles, the antiviral activity of the highest nontoxic concentration of GO against influenza A H1N1 in MDCK cells was studied.Results: GO treatments resulted in substantial decreases in virus titers, as shown via hemagglutination assay, TCID50 assay and real-time PCR analysis.Conclusion: This study emphasizes that GO nanoparticles have a high level of effectiveness against influenza A H1N1 viruses, making them an intriguing option for various antiviral uses.

Pseudorabies Virus UL4 protein promotes the ASC-dependent inflammasome activation and pyroptosis to exacerbate inflammation.

Pseudorabies virus (PRV) infection causes systemic inflammatory responses and inflammatory damages in infected animals, which are associated with the activation of inflammasome and pyroptosis in infected tissues. Here, we identified a critical function of PRV non-structural protein UL4 that enhanced ASC-dependent inflammasome activation to promote pyroptosis. Whereas, the deficiency of viral UL4 was able to reduce ASC-dependent inflammasome activation and the occurrences of pyroptosis. Mechanistically, the 132-145 aa of UL4 permitted its translocation from the nucleus to the cytoplasm to interact with cytoplasmic ASC to promote the activation of NLRP3 and AIM2 inflammasome. Further research showed that UL4 promoted the phosphorylation levels of SYK and JNK to enhance the ASC phosphorylation, which led to the increase of ASC oligomerization, thus promoting the activation of NLRP3 and AIM2 inflammasome and enhanced GSDMD-mediated pyroptosis. In vivo experiments further showed that PRV UL4 (132DVAADAAAEAAAAE145) mutated strain (PRV-UL4mut) infection did not lead to a significant decrease in viral titers at 12 h. p. i, but it induced lower levels of IL-1β, IL-18, and GSDMD-NT, which led to an alleviated inflammatory infiltration and pathological damage in the lungs and brains, and a lower death rate compared with wild-type PRV strain infection. Taken together, our findings unravel that UL4 is an important viral regulator to manipulate the inflammasome signaling and pyroptosis of host cells to promote the pathogenicity of PRV, which might be further exploited as a new target for live attenuated vaccines or therapeutic strategies against pseudorabies in the future.

Antibody Persistence and Risk of COVID-19 Infection: Insights from Modeling.

In this post hoc exploratory study of the APHP-COVIBOOST trial (NCT05124171), we used statistical modeling to describe the evolution of neutralizing antibody (nAb) titers over time, asses its impact on SARS-CoV-2 infection, and explore potential differences between three booster vaccine formulations (D614, B.1.351, and BNT162b2). Antibody titers were measured for 208 adult participants at day 28, 3 months, and 6 months using a microneutralization assay against different Omicron subvariants. We developed four specific Bayesian statistical models based on a core model, accounting for vaccine-specific antibody decline, boosting of nAb for breakthrough infection, and risk of infection according to nAb levels. The model findings were cross-verified using another validated microneutralization assay. The decrease in nAb titers was significantly lower for the B.1.351 vaccine than for the other booster formulations. An inverse relationship was found between risk of infection upon exposure and nAb levels. With Omicron BA.1 data, these results translated into a positive relative vaccine efficacy against any infection over 6 months for the B.1.351 vaccine compared to the BNT162b2 (31%) and D614 (21%) vaccines. Risk of infection decreased with increasing nAb titers for all vaccines. Statistical models predicted significantly better antibody persistence for the B.1.351 booster formulation compared to the other evaluated vaccines.

Nipocalimab in Early-Onset Severe Hemolytic Disease of the Fetus and Newborn

BackgroundIn early-onset severe hemolytic disease of the fetus and newborn (HDFN), transplacental transfer of maternal antierythrocyte IgG alloantibodies causes fetal anemia that leads to the use of high-risk intrauterine transfusions in order to avoid fetal hydrops and fetal death. Nipocalimab, an anti–neonatal Fc receptor blocker, inhibits transplacental IgG transfer and lowers maternal IgG levels.MethodsIn an international, open-label, single-group, phase 2 study, we assessed treatment with intravenous nipocalimab (30 or 45 mg per kilogram of body weight per week) administered from 14 to 35 weeks’ gestation in participants with pregnancies at high risk for recurrent early-onset severe HDFN. The primary end point was live birth at 32 weeks’ gestation or later without intrauterine transfusions as assessed against a historical benchmark (0%; clinically meaningful difference, 10%).ResultsLive birth at 32 weeks’ gestation or later without intrauterine transfusions occurred in 7 of 13 pregnancies (54%; 95% confidence interval, 25 to 81) in the study. No cases of fetal hydrops occurred, and 6 participants (46%) did not receive any antenatal or neonatal transfusions. Six fetuses received an intrauterine transfusion: five fetuses at 24 weeks’ gestation or later and one fetus before fetal loss at 22 weeks and 5 days’ gestation. Live birth occurred in 12 pregnancies. The median gestational age at delivery was 36 weeks and 4 days. Of the 12 live-born infants, 1 received one exchange transfusion and one simple transfusion and 5 received only simple transfusions. Treatment-related decreases in the alloantibody titer and IgG level were observed in maternal samples and cord blood. No unusual maternal or pediatric infections were observed. Serious adverse events were consistent with HDFN, pregnancy, or prematurity.ConclusionsNipocalimab treatment delayed or prevented fetal anemia or intrauterine transfusions, as compared with the historical benchmark, in pregnancies at high risk for early-onset severe HDFN. (Funded by Janssen Research and Development; UNITY ClinicalTrials.gov number, NCT03842189.)

EVALUATION OF THE EFFICACY OF CHLORINE-CONTAINING COMMERCIAL PRODUCTS FOR WATER DECONTAMINATION AGAINST COLIFORM BACTERIA

Problem. Water is a key factor in the transmission of intestinal infections. During war conflicts, the risk of outbreaks of such infections increases due to infrastructure damage, the inaccessibility of central water supplies, and the impossibility of governmental institutions to control drinking water quality. In such situations, the need arises for household water treatment methods. Aim. To evaluate the efficacy of seven commercial water treatment products available in the Ukrainian market against enteric bacteria and to compare their efficacy. Methods. The activity of water purification products against the model microorganism Escherichia coli ATCC25922 was evaluated using serial dilution methods followed by viable count assessment. The main results: High efficacy of the studied preparations against enteric bacteria was detected. In each test, a significant decrease in the initial titer of Escherichia coli from 1,2·10 6 CFU/cm 3 to ˂ 10 CFU/cm 3 was observed after the exposure time declared by the manufacturer. Conclusions: The studied water treatment products from Ukrainian and foreign manufacturers were effective against enteric bacteria and met the WHO criteria for efficiency, regardless of the nature of the active compound (chlorine dioxide, sodium dichloroisocyanurate, or polyhexamethylene guanidine hydrochloride).

Dilution of humoral immunity: Results from a natural history study of healthy total knee arthroplasty patients.

The incidence of prosthetic joint infection (PJI) following elective primary total knee arthroplasty (TKA) is very low but serious risk remains. To identify unknown risk factors, we completed a natural history study of IgG specific forStaphylococcus aureus antigens previously phenotyped as protective (anti-Atl) and pathogenic (anti-Isd). Twenty-five male and 25 female optimized patients 50-85 years of age and BMI 24-39 undergoing primary TKA were prospectively enrolled. Blood sampling was performed preoperatively, postoperative Day 1, and at 2, 6, and 12 weeks, to assess serum cytokine, anti-staphylococcal IgG levels and anti-tetanus toxoid IgG measured via custom Luminex assay. Clinical, demographic, and PROMIS-10 data were collected with outcomes to 2 years postop. All participants completed the study and 2-year follow-up. No patients were readmitted or noted to develop a surgical site infection or serious adverse event, and patient-reported outcomes were improved. Serology revealed a highly significant decrease in six out of eight antibody titers against specific S. aureus antigens on Day 1 (p < 0.0001), five of which normalized to preoperative levels within 2 weeks. These changes were commensurate with a decrease and recovery of anti-tetanus toxoid titers, and a 20% drop in hemoglobin 13.8 ± 1.7 at preop to 11.1 ± 1.8 mg/dL on Day 1 (p < 0.0001). After TKA, a significant decrease in humoral immunity commensurate with blood loss and hemodilution was recorded. This decrease in circulating anti-staphylococcal antibodies in the early postop period may represent a periprosthetic joint infection risk factor for patients.

Dual Guardians of Immunity: FoRab10 and FoRab29 in Frankliniella occidentalis Confer Resistance to Tomato Spotted Wilt Orthotospovirus.

Rab GTPase is critical for autophagy processes and is implicated in insect immunity against viruses. In this study, we aimed to investigate the role of FoRabs in the autophagic regulation of antiviral defense against tomato spotted wilt orthotospovirus (TSWV) in Frankliniella occidentalis. Transcriptome analysis revealed the downregulation of FoRabs in viruliferous nymph and adults of F. occidentalis in response to TSWV infection. Manipulation of autophagy levels with 3-MA and Rapa treatments resulted in a 5- to 15-fold increase and a 38-64% decrease in viral titers, respectively. Additionally, interference with FoRab10 in nymphs and FoRab29 in adults led to a 20-90% downregulation of autophagy-related genes, a decrease in ATG8-II (an autophagy marker protein), and an increase in the TSWV titers by 1.5- to 2.5-fold and 1.3- to 2.0-fold, respectively. In addition, the leaf disk and the living plant methods revealed increased transmission rates of 20.8-41.6 and 68.3-88.3%, respectively. In conclusion, FoRab10 and FoRab29 play a role in the autophagic regulation of the antiviral defense in F. occidentalis nymphs and adults against TSWV, respectively. These findings offer insights into the intricate immune mechanisms functional in F. occidentalis against TSWV, suggesting potential targeted strategies for F. occidentalis and TSWV management.

Lack of Serological Response by Delivery to Syphilis Treatment Does Not Impact Pregnancy Outcomes.

Objectives: Maternal syphilis can lead to serious adverse pregnancy outcomes, including neonatal death. A 4-fold decline in blood non-treponemal titer at six months after the treatment of syphilis compared to the baseline is considered as an adequate serological response. However, the duration of normal human gestation does not allow the ascertainment of an adequate serological response. Aim: The aim of this study was to assess correlations between the lack of a 4-fold decrease in non-treponemal titer by delivery after syphilis treatment and fetal and newborns' condition and serological outcomes. Methods: Fourteen pregnant patients (gestational age 16-22 weeks) diagnosed with early syphilis (secondary or latent) were treated with intramuscular benzathine penicillin and subsequently monitored clinically, serologically, and ultrasonographically at monthly intervals. Based on the non-treponemal test results at delivery, patients were stratified into two groups: those with a 4-fold decline in titers and those without such a decline. All newborns were clinically and serologically assessed for congenital syphilis at birth and then monitored until serological tests became negative. Results: Fifty percent of the included women did not achieve a 4-fold decline in non-treponemal titer by delivery. Patients from the group showing a 4-fold decline in RPR titer at delivery and those without such a decline did not differ in basic demographic and clinical characteristics or in ultrasound parameters used for fetal assessment. Based on the clinical and laboratory assessments of newborns on the day of delivery and during a 6-month follow-up, none were diagnosed with congenital syphilis or required treatment for syphilis. Conclusions: The lack of an adequate serological response to syphilis therapy by delivery among patients treated between 16 and 22 weeks of pregnancy does not appear to be associated with adverse fetal and neonatal outcomes.

Control of Field Infectious Bronchitis Virus Genotype GI-23 (Variant 2) Using Combined Heterologous Vaccine Genotype Strains GI-13 (1/96) and GI-1 (H120)

Infectious bronchitis (IB) is a disease with significant economic impacts both on the costs of control strategies and on productive losses. Various vaccination protocols are applied, depending on homologous or heterologous protection against IB and finding the optimal balance between costs and benefits as a choice by a responsible veterinarian. The current case study aimed to demonstrate the efficacy of a heterologous vaccine combination against field IBV GI-23 (Variant 2) infection when vaccination quality was properly monitored. Two groups, each consisting of six flocks, were examined before and after improving the quality of IB vaccine application in the hatchery. These groups were vaccinated with H-120 and 1/96 vaccine strains for heterologous protection. The study involved field visits, necropsies, serology via ELISA, and oropharyngeal sampling for RT-PCR follow-up activities. Moreover, performance parameters including average body weight, feed conversion ratio, and 7 days plus total mortality were analyzed at the end of the production cycle at 40-45 days of age. Results indicated that the group with enhanced vaccination quality in the hatchery exhibited a significant decrease in IBV titers and an absence of IBV GI-23 field infection. Additionally, there was an improvement in performance data in terms of average body weight, FCR and total mortality. Hatchery vaccination proved to be more controllable and practical compared to traditional on-farm vaccination, ensuring better control of the vaccination process and massive coverage of the farm population. Keywords: Heterologous protection, Infectious bronchitis, Vaccine strain 1/96, Variant 2

Differences in SARS-CoV-2 antibodies depending on age, blood group, and sex in a Swedish blood donor cohort

This study aimed to describe differences in prevalence and the long-term presence of nucleocapsid antibodies (N-antibodies) elicited by SARS-CoV-2 infection in a Swedish blood donor population not subjected to lockdown. We tested 20,651 blood donor samples for nucleocapsid antibodies from the beginning of March 2020 and 27 months onwards using the Roche Elecsys Anti-SARS-CoV-2 assay. The proportion of positive SARS-CoV-2 antibody samples was determined each week. After the exclusions of one-time donors and subjects with incomplete data, 19,726 samples from 4003 donors remained. Differences in antibody prevalences stratified for age, sex, and blood groups (ABO and RhD) were determined, as well as antibody loss and recovery. Lower antibody prevalence was seen for older donors, blood group AB, and RhD-negative subjects. A significant decrease in antibody titer between the first and the second antibody-positive donation was seen for the whole study group, females, older subjects, blood group O, AB, and RhD-positive subjects. The titer waned below the detection limit in 60 (3.0%) of 1983 N-antibody-positive donors, and for 18 of these donors, a second episode with antibodies was detected. We showed that N-antibodies persist for months or years and that surprisingly few antibody-positive donors lost their antibodies. We also conclude that antibody prevalence in a Swedish population never subject to lockdown did not apparently differ from populations that were subject to stricter regulations.

RBD design increases the functional antibody titers elicited by SARS-CoV-2 spike vaccination

Most COVID-19 vaccines contain the SARS-CoV-2 spike protein as an antigen, but they lose efficacy as neutralizing antibody titers wane and escape variants emerge. Modifying the spike antigen to increase neutralizing antibody titers would help counteract this decrease in titer. We previously used a structure-based computational design method to identify nine amino acid changes in the receptor-binding domain (RBD) of spike that stabilize the RBD and increase the neutralizing antibody titers elicited by vaccination. Here, we introduce those enhancing amino acid changes into a full-length spike (FL-S-2P) ectodomain representative of most approved vaccine antigens. These amino acid changes can be incorporated into the FL-S-2P protein without negatively effecting expression or stability. Furthermore, the amino acid changes improved functional antibody titers in both mice and monkeys following vaccination. These amino acid changes could increase the duration of protection conferred by most COVID-19 vaccines.

Proof of stability of an RSV Controlled Human Infection Model challenge agent

In 2018, SGS Belgium NV developed RSV-NICA (Respiratory Syncytial Virus-Nasobronchial Infective Challenge Agent), an RSV type A challenge agent for use in RSV Controlled Human Infection Model (CHIM) studies.It is widely recognized that the stability of RSV can be influenced by a variety of environmental parameters, such as temperature and pH. Consequently, our objective was to evaluate the stability of the viral titer of RSV-NICA following five years of controlled storage and to determine the uniformity of the viral titers across different vials of a GMP-qualified batch of RSV-NICA. In addition, we examined the capacity of RSV-NICA to infect human primary airway epithelial cells (MucilAir™), the principal target cells of RSV, and evaluated the influence of single and recurrent freeze–thaw cycles on the infectious viral titer of the challenge agent.The aliquoted RSV-NICA virus stock was subjected to standard virological and molecular methods to gather data on the titer and consistency of the viral titer contained within 24 representative vials of the stock. Our findings illustrate that over a span of five years of cryo-storage, the infectious viral titer in 75% of the tested vials exhibited a comparable average infectious viral titer (4.75 ± 0.06 vs 4.99 ± 0.11; p-value = 0.14). A considerable reduction down to an undetectable level of infectious virus was observed in the remaining vials. RSV-NICA demonstrated its capacity to effectively infect differentiated human airway epithelial cells, with active virus replication detected in these cells through increasing RSV genome copy number over time. Virus tropism for ciliated cells was suggested by the inhibition of cilia beating coupled with an increase in viral RNA titers. No discernable impact on membrane barrier function of the epithelial lung tissues nor cytotoxicity was detected. Pooling of vials with infectious titers > 4.0 log10 TCID50/ml and freeze-thawing of these combined vials showed no deterioration of the infectious titer. Furthermore, pooling and re-aliquoting of vials spanning the entire range of viral titers (including vials with undetectable infectious virus) along with subjecting the vials to three repeated freeze–thaw cycles did not result in a decrease of the infectious titers in the tested vials.Taken together, our findings indicate that long-term cryo-storage of vials containing RSV-NICA challenge agent may influence the infectious viral titer of the virus, leading to a decrease in the homogeneity of this titer throughout the challenge stock. However, our study also demonstrates that when heterogeneity of the infectious titer of an RSV stock is observed, rounds of pooling, re-aliquoting and subsequent re-titration serve as an effective method not only to restore the homogeneity of the infectious titer of an RSV-A stock, but also to optimize patient-safety, scientific and operational aspects of viral inoculation of study participants during at least the period of one RSV CHIM trial. RSV-NICA is a stable, suitable CHIM challenge agent that can be utilized in efficacy trials for RSV vaccines and antiviral entities.

Ben-JNK signaling is required for host mortality during Periplaneta fuliginosa densovirus infection.

Cockroaches are widely acknowledged as significant vectors of pathogenic microorganisms. The Periplaneta fuliginosa densovirus (PfDNV) infects the smoky-brown cockroach P. fuliginosa and causes host mortality, which identifies the PfDNV as a species-specific and environmentally friendly biopesticide. However, although the biochemical characterization of PfDNV has been extensively studied, the immune response against PfDNV remains largely unclear. Here, we investigated the replication of PfDNV and its associated pathological phenotype in the foregut and hindgut. Consequently, we dissected and performed transcriptome sequencing on the foregut, midgut, and hindgut separately. We revealed the up-regulation of immune response signaling pathway c-Jun N-terminal kinase (JNK) and apoptosis in response to viral infection. Furthermore, knockdown of the JNK upstream gene Ben resulted in a decrease in virus titer and delayed host mortality. Taken together, our findings provide evidence that the Ben-JNK signaling plays a crucial role in PfDNV infection, leading to excessive apoptosis in intestinal tissues and ultimately resulting in the death of the host. Our results indicated that the host response to PfDNV fosters viral infection, thereby increasing host lethality. This underscores the potential of PfDNV as a viable, environmentally friendly biopesticide. © 2024 Society of Chemical Industry.

Immunogenicity of Covishield vaccine in patients with autoimmune rheumatic diseases.

The Coronavirus disease 2019 (COVID-19) pandemic has been the biggest threat to humankind during the last 3 years. It has caused the loss of more than 6.9 million precious lives across the world. The only method by which the massacre could be stopped was by mass vaccination or mass immunization. The patients suffering from autoimmune rheumatic disorders (AIRDs) and treated with immunosuppressants were the high-priority candidates for vaccination. However, the data regarding the efficacy of COVID-19 vaccines in this group of patients are very less. Hence, this study was planned to study the immunogenicity of Covishield in patients with AIRDs attending the rheumatology OPD at DMCH, Ludhiana. It was a prospective cohort study and was planned by the Department of Biochemistry and Department of Clinical Immunology and Rheumatology at Dayanand Medical College and Hospital, Ludhiana. Fifty patients with AIRDs attending the DMCH rheumatology OPD and 52 age and sex-matched healthy controls who had received two doses of Covishield vaccine were included in this study. Patients having any other immunosuppressive conditions like uncontrolled diabetes, hepatitis, malignancy or HIV were excluded. Patients who had suffered from previous laboratory-confirmed COVID-19 infection (by RT-PCR) were also excluded. Blood samples were collected following all aseptic precautions from patients and controls on the 28th day after administration of a second dose of Covishield vaccine and total antibodies to the severe acute respiratory syndrome coronavirus 2 spike (S) protein receptor binding domain was measured using Elecsys Anti-SARS-CoV-2 S kit from Roche. It was observed that no significant difference was there in antibody titre between cases and controls (6213 ± 4418 vs. 8331 ± 7979, P = 0.1022). It was also observed that no statistically significant difference in antibody titre in cases without prednisolone and those taking treatment with prednisolone was found (P = 0.7058). A similar observation was found in terms of methotrexate also (P = 0.457). No significant difference in antibody titres was there when compared with controls (for prednisolone, P = 0.169, for methotrexate, P = 0.078). We found that only the patients receiving mycophenolate mofetil showed a statistically significant decrease in antibody titre in comparison to healthy controls (P = 0.03). Our study showed no statistically significant difference in antibody titres between patients suffering from different AIRDs. Our study supplements the fact that patients with AIRDs in India can receive Covishield as the primary vaccine against COVID-19 without concerns regarding decreased immunogenicity or increased adverse effects.

Антимікробна та противірусна активність нанокомпозитів на основі поліелектролітних комплексів з наночастинками срібла

Recently, nanocomposite materials containing nanoparticles of metals such as silver, copper and zinc oxide have attracted most attention due to their pronounced pharmacological properties, such as antimicrobial, antiviral, antiinflammatory, immunomodulatory ability and high stability in extreme conditions. Polyelectrolyte complexes based on polymers of natural origin, namely polysaccharides of chitosan and pectin, which can stabilize nanoparticles of a smaller size than individual polymers have significant potential for creation of silver-containing nanocomposites. The aim of this article is to study the antimicrobial and antiviral activity of silver-containing nanocomposites based on polyelectrolyte complexes. Methods. Peculiarities of the structural organization of silver-containing nanocomposites were investigated by the method of wide-angle scattering on an XRD-7000 diffractometer. The morphology of Ag nanoparticles in polymer matrixes were studied by transmission electron microscopy method (transmission electron microscope JEOL 100 CXII). The antimicrobial activity of silver-containing nanocomposites was determined by agar diffusion assays against opportunistic pathogens Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. Cytotoxicity and antiviral activity were investigated using the MTT method and staining by gentian violet. Results. Analysis of wide-angle X-ray diffractograms of silver-containing nanocomposites based on polyelectrolyte complexes Na-CMC (pectin) – chitosan showed that at reduction of Ag+ ions to metallic silver, there are two low-intensity diffraction maxima at 2θm ~ 380 and 440 in the diffractograms. These maxima correspond to the crystallographic planes of the face-centered cubic lattice of silver, are characterized by indices (111) and (200), respectively, and confirm the presence of metallic silver in the polymer system. Analysis of micrographs of silver-containing nanocomposites based on Na-CMC and chitosan showed that larger nanoparticles are formed with increasing the molecular weight of chitosan. The dependence of the size of silver nanoparticles on the wavelength of ultraviolet radiation at reduction of silver ion in polyelectrolyte-metal complexes Na-CMC–Ag+–chitosan of low molecular weight was also revealed. In particular, smaller particles are formed under irradiation by light with a shorter wavelength (λ =254 nm) than at λ=365 nm. Silver-containing nanocomposites Na-СMC-Ag-chitosan and pectin citrus-Ag-chitosan, obtained by reduction of Ag+ ions under ultraviolet irradiation at a wavelength λ = 365 nm and λ = 254 nm, exhibit high antimicrobial activity against the test cultures of microorganisms S. aureus, E. coli, and P. aeruginosa C. albicans. No significant dependence of antimicrobial activity on the molecular weight of the studied samples was noted: the obtained data were within close limits and had close values. In addition, no dependence of antimicrobial activity on the type of investigated test cultures of microorganisms was observed either. Nanocomposites based on Na-CMC-chitosan (λ = 365 nm) inhibited infection titer HSV-1 by (3.72–5.45) lgTCID50/mL, whereas the decrease in titer during incubation with samples based on citrus pectin-chitosan was within (2.39–2.42) lgTCID50/mL. A dose-dependent relationship between molecular weight of chitosan and reduction of infection titer was observed. It was found that silver-containing nanocomposites formed by reduction of silver ions in polyelectrolyte-metal complexes under ultraviolet radiation of different wavelengths had no cytotoxic effect on cells of MDCK and BHK. Conclusions. The investigated silver-containing nanocomposites based on Na-CMC (pectin)-chitosan polyelectrolyte complexes show antimicrobial activity against test cultures of S. aureus, E. coli P. aeruginosa, and C. albicans along with antiviral activity against herpes simplex virus type 1 and influenza virus. It was established that the obtained nanocomposites did not show a cytotoxic effect on MDCK and BHK cells. The obtained data allow us to assert that investigated silver-containing nanocomposites are promising antimicrobial means for the development of new effective strategies against microorganisms and viruses and improvement of the population health.

Infection of Human Macrophage-Like Cells by African Swine Fever Virus.

The African swine fever (ASF) virus (ASFV) and ASF-like viral sequences were identified in human samples and sewage as well as in different water environments. Pigs regularly experience infections by the ASFV. The considerable stability of the virus in the environment suggests that there is ongoing and long-term contact between humans and the ASFV. However, humans exhibit resistance to the ASFV, and the decisive factor in developing infection in the body is most likely the reaction of target macrophages to the virus. Therefore, this study aimed to characterize the responses of human macrophages to the virus and explore the distinct features of the viral replication cycle within human macrophages. The ASFV Armenia/07 strain was used in all experiments. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the ASFV gene expression; flow cytometry analysis was performed to evaluate the effects of the inactive and active ASFV (inASFV and aASFV) treatments on the phenotype of THP-1-derived macrophages (Mφ0) and inflammatory markers. Moreover, other methods such as cell viability and apoptosis assays, staining techniques, phagocytosis assay, lysosome-associated membrane protein (LAMP-1) cytometry, and cytokine detection were used during experiments. Our findings showed that the virus initiated replication by entering human macrophages. Subsequently, the virus shed its capsid and initiated the transcription of numerous viral genes, and at least some of these genes executed their functions. In THP-1-derived macrophages (Mφ0), the ASFV implemented several functions to suppress cell activity, although the timing of their implementation was slower compared with virus-sensitive porcine alveolar macrophages (PAMs). Additionally, the virus could not complete the entire replication cycle in human Mφ0, as indicated by the absence of viral factories and a decrease in infectious titers of the virus with each subsequent passage. Overall, the infection of Mφ0 with the ASFV caused significant alterations in their phenotype and functions, such as increased TLR2, TLR3, CD80, CD36, CD163, CXCR2, and surface LAMP-1 expression. Increased production of the tumor necrosis factor (TNF) and interleukin (IL)-10 and decreased production of interferon (IFN)-α were also observed. Taken together, the virus enters human THP-1-derived macrophages, starts transcription, and causes immunological responses by target cells but cannot complete the replicative cycle. These findings suggest that there may be molecular limitations within human macrophages that at least partially restrict the complete replication of the ASFV. Understanding the factors that hinder viral replication in Mφ0 can provide valuable insights into the host-virus interactions and the mechanisms underlying the resistance of human macrophages to the ASFV.

Changes in the avids of IgG antibodies to the S protein of SARS-CoV-2 after coronavirus infection in medical workers of a temporary infections hospital

BACKGROUND: The effector capabilities of humoral immunity are determined not only by the amount of specific antibodies produced in response to an antigenic effect, but also by their qualitative characteristics, which include avidity ― the total strength of binding to the antigen, which determines the duration and effectiveness of post-infectious immunity to SARS-CoV-2.&#x0D; AIM: Is a selective study of the quantity and avidity of IgG antibodies to SARS-CoV-2 over time among medical workers of a temporary infectious diseases hospital in Kazan ― convalescents of COVID-19, during the period from July 2020 to July 2021.&#x0D; MATERIALS AND METHODS: Determination of IgG to the S antigen of SARS-CoV-2 by ELISA was carried out using the test system SARS-CoV-2-IgG quantitative-ELISA-BEST (Vector-Best, Russia) and expressed in BAU/ml (binding antibody units). Antibody avidity was determined using a 4.0 M urea solution and expressed as avidity indices. 1, 4 and 7 months after COVID-19 asymptomatic (n=34); mild severity (n=42); moderate severity (n=29); reinfected (n=34). When statistically processing the data, descriptive statistics methods and the Wilcoxon matched data test were used. Differences were considered significant at p 0.05.&#x0D; RESULTS: IgG avidity to SARS-CoV-2 depended on the severity of COVID-19. The highest rates of avidity indices were found in the group of those who had a moderate form of COVID-19. If in mild and asymptomatic forms there was a parallel decrease in avidity indices and IgG titer, then in moderate forms an increase in antibody titer was accompanied by a decrease in their avidity 4 months after the infection. 7 months after seroconversion, the IgG level decreased almost twofold, both in mild, asymptomatic and moderate forms. In the group of medical workers who had COVID-19 repeatedly, the initially low levels of avidity indices and antibody titers increased in parallel, while avidity indices after 7 months did not decrease, but remained high. Differences in avidity indices determined the subsequent formation of different trends in the development of the humoral immune response, which were mainly characterized by an uneven decrease in IgG and persistence of IgM antibodies for more than 1 month.&#x0D; CONCLUSIONS: The research results expand the understanding of the mechanisms of formation of the humoral immune response and the avidity of IgG antibodies against SARS-CoV-2 in the risk group ― medical workers. The level of humoral immunity decreases in the first six months and varies depending on the severity of COVID-19. The data obtained can be used to identify categories of increased risk of SARS-CoV-2 infection among healthcare workers, make decisions about immunorehabilitation and revaccination against COVID-19.

Duration of antibody response to the receptor binding domain of SARS-CoV-2 in infected or vaccinated individuals – A one year retrospective cohort study

The 2019 coronavirus (COVID-19) pandemic raised many scientific and medical questions. Of interest are the duration and effectiveness of the humoral immune response, especially since part of the pandemic occurred in the presence of anti-SARS-CoV-2 vaccines. We retrospectively studied 564 serum samples from 393 post-infected and vaccinated individuals to investigate the longevity and magnitude of the anti-spike IgG response. Our results showed that SARS-CoV-2 anti-spike IgG antibodies are retained for nine-twelve months, in both groups. In the vaccinated group we found higher IgG levels, but with a steeper decrease in titer over the study period. The recovered group’s antibody levels correlated well with the national infection trendline for 2021. Both groups showed different, but distinct neutralizing capabilities towards RBD. The anti-Spike IgG response was sustained and efficient, independently of the triggering event, infection or vaccination, with the adaptive capacity against new viral variants being more valuable after infection.

Assessment of the Impact of Polycyclic Derivatives of the Frame Series on the Replicative Properties of the SARS-CoV-2 Virus in an &lt;I&gt;in vitro&lt;/I&gt; Experiment

The aim of the work was to determine the cytotoxicity and the influence of polycyclic derivatives of the framework series on the replicative properties of the SARS-CoV-2 virus in Vero-E6 cell culture in vitro. Materials and methods. The virus inhibiting effect of 50 adamantane and bicyclo[3.3.1]nonane derivatives with carbocyclic and heterocyclic substituents was investigated. The studies were carried out on Vero-E6 cell culture by assessing the cytopathic effect of the virus. The impact of the compounds on the replicative properties of the SARS-CoV-2 virus was estimated by the decrease in virus titer in the presence of the compounds compared to the control. Based on the virus titer values in the presence of a series of successively decreasing concentrations of the compound, the 50 % effective concentration was calculated.Results and discussion. A study of polycyclic derivatives of the framework series has identified two compounds with antiviral properties against the SARS-CoV-2 virus. Among bicyclo[3.3.1]nonane derivatives containing heterocyclic fragments, compound No. 15144 has showed an inhibitory effect against the SARS-CoV-2 virus. The protective effect of the compound was manifested in maximum tolerable concentration (MTC) (70.0 μg/ml) and ½ MTC (35.0 µg/ml). A decrease in virus titers under the influence of MTC by 0.95 lg TCD50/ml, in ½ MTC (35.0 μg/ml) – by 0.35 lg TCID50/ml has been detected. The effective concentration (EC50) value of the compound No. 15144 was 64.0 μg/ml, the MTC/EC50 ratio was 1.09. Compound No. 14838 (adamantane derivative containing carbocyclic fragments) had less pronounced antiviral activity. As a result of research, it has been established that sample No. 14838 at a dose of MTC (45.0 μg/ml) reduces the infectious titer by 0.78 lg TCD50/ml, in ½ MTC (22.5 μg/ml) by 0.15 lg TCD50/ml compared to the control. The EC50 value of compound No. 14838 was 37.0 μg/ml, the MTC/EC50 ratio was 1.22.

Optimizing lentiviral vector formulation conditions for efficient ex vivo transduction of primary human T cells in chimeric antigen receptor T-cell manufacturing

Background aimsChimeric antigen receptor (CAR) T-cell products are commonly generated using lentiviral vector (LV) transduction. Optimal final formulation buffer (FFB) supporting LV stability during cryostorage is crucial for cost-effective manufacturing. MethodsTo identify the ideal LV FFB composition for ex vivo CAR-T production, primary human T cells were transduced with vesicular stomatitis virus G-protein (VSV-G) -pseudotyped LVs (encoding a reporter gene or an anti-CD19-CAR). The formulations included phosphate-buffered saline (PBS), HEPES, or X-VIVOTM 15, and stabilizing excipients. The functional and viral particle titers and vector copy number were measured after LV cryopreservation and up to 24 h post-thaw incubation. CAR-Ts were produced with LVs in selected FFBs, and the resulting cells were characterized. ResultsPost-cryopreservation, HEPES-based FFBs provided higher LV functional titers than PBS and X-VIVOTM 15, and 10% trehalose-20 mM MgCl2 improved LV transduction efficiency in PBS and 50 mM HEPES. Thawed vectors remained stable at +4°C, while a ≤ 25% median decrease in the functional titer occurred during 24 h at room temperature. Tested excipients did not enhance LV post-thaw stability. CAR-Ts produced using LVs cryopreserved in 10% trehalose- or sucrose-20 mM MgCl2 in 50 mM HEPES showed comparable transduction rates, cell yield, viability, phenotype, and in vitro functionality. ConclusionA buffer consisting of 10% trehalose-20 mM MgCl2 in 50 mM HEPES provided a feasible FFB to cryopreserve a VSV-G -pseudotyped LV for CAR-T-cell production. The LVs remained relatively stable for at least 24 h post-thaw, even at ambient temperatures. This study provides insights into process development, showing LV formulation data generated using the relevant target cell type for CAR-T-cell manufacturing.